build: update toolchain to Go 1.25.5

[jrasell]

Resolves for CVE-2025-61727 and CVE-2025-61729, the latter which is within the scanning DB and causing builds to fail.

It does not look like we use either impacted code path within the compiled code. There are a couple of tests that use x509.HostnameError.

Go release: https://github.com/golang/go/issues?q=milestone%3AGo1.25.5+label%3ACherryPickApproved

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[pkazmierczak]

LGTM